The Jer. Talmud (Taanit 24, 1) tells us that when Bar Kochba's went to a battle he was saying:
"וכד (הוא) דהוה נפק לקרבא הוה אמר ריבוניה דעלמא לא תסעוד ולא תכסוף
(תהילים ס׳:י״ב) הלא אתה אלהים זנחתנו ולא תצא בצבאותינו"
So he was saying when going to a battle: "The Almighty Ruler of the World! Don't help us but don't despise (?) us" (My translation).
In my understanding, the Jewish tradition regarding approaching war is to pray for G-d's help and maximize our reliance on Him, based on many verses in the Torah, like "ה' ילחם לכם ואתם תחרישון", Moses preventing an attempt to go to a fight without G-d's support (num 13) and many more.
What is the meaning of this statement (if not as Pshat) and what can be said of Bar Kochba when he acted exactly the opposite of the Jewish military?